Date of Award

Summer 2015

Document Type


Degree Name

Master of Science (MS)



First Advisor

Lobner, Douglas C.

Second Advisor

Stover, Sheila

Third Advisor

Liu, Dawei


Introduction: Direct pulp capping involves placing a material over the exposed pulp in order to maintain its vitality. For decades, calcium hydroxide (CH) has served as the gold standard for this purpose, but its toxicity to the pulp may negatively impact treatment outcomes. Mineral Trioxide Aggregate (MTA) has become a popular alternative based partly on its excellent biocompatibility. Pulp-capped teeth are often restored with highly toxic composite materials, but the pulp capping material’s ability to alter these toxic effects has never been investigated. The purpose of this in vitro study is to determine the effects of Dycal, a CH-based cement, and ProRoot MTA on the toxicities of two popular restorative composites, Flow Line and Durafill VS. Materials and Methods: Human dental pulp cells were cultured and exposed to Dycal or MTA for 48 hours. Dycal and MTA were then removed and either Flow Line or Durafill VS was added to cell cultures for 24 hours. Toxicity was determined using the LDH release assay before and after the addition of the composite material. Results: Dycal demonstrated a high level of toxicity that correlated with the amount of material placed in cell culture. MTA was nontoxic even in amounts at which Dycal was highly toxic. Exposure of pulp cells to Dycal resulted in decreased toxicity of Durafill VS and had no effect on Flow Line toxicity. MTA exposure resulted in enhanced Flow Line toxicity and had no effect on the toxicity of Durafill VS. Conclusions: These results show that calcium hydroxide and MTA are capable of altering the toxicity of composite restorative materials. MTA may enhance the toxicity of some composites, while Dycal may have an inhibitory effect. More studies are needed to determine the clinical significance of these effects.